A magnetic storage system typically includes one or more magnetic recording disks having surfaces from which data may be read and to which data may be written by a read/write transducer or “head.” The transducer is supported by an air-bearing slider that has a top surface attached to an actuator assembly via a suspension, and a bottom surface having an air-bearing design of a desired configuration to provide favorable flying height characteristics. As a disk begins to rotate, air enters the leading edge of the slider and flows in the direction of the trailing edge of the slider. The flow of air generates a positive pressure on the air-bearing surface of the slider to lift the slider above the recording surface. As the spindle motor reaches the operating RPM, the slider is maintained at a nominal flying height over the recording surface by a cushion of air. Then, as the spindle motor spins down, the flying height of the slider drops.
The manner in which a slider is manufactured can affect flying height. Preferably, variations in the physical characteristics of the slider, e.g., those due to manufacturing tolerances, should not substantially alter the flying height of the slider. If this result is not achieved, the slider's nominal flying height must be increased to compensate for variations between sliders.
A number of technologies may be employed to pattern such slider surfaces. For example, mechanical processes such as cutting or abrading have been proposed to remove material from a slider surface. Similarly, non-mechanical processes such as laser ablation, in which high intensity light is used to evaporate material from sliders, have also been proposed. Alternatively, material may be added to slider surfaces to alter their configuration to provide favorable flying height characteristics. In some instances, these technologies have been used in conjunction with photolithographic and other semiconductor processing techniques. In addition, these technologies may be adapted to pattern a plurality of air-bearing slider surfaces simultaneously and/or systematically.
Thus, several approaches have been developed to facilitate the handling of a plurality of sliders for simultaneous and/or systematic patterning of their air-bearing surfaces. For example, U.S. Pat. No. 5,932,113 to Kurdi et al. describes a method for preparing the air-bearing surface of a slider for etch patterning. The method involves applying first and second thin films comprising, respectively, first and second air-bearing surfaces, to a carrier in a manner such that the first and second thin film are separated by a recess. An adhesive film is applied over the first and second thin films adjacent to the first and second air-bearing surfaces. Then, a curable acrylate adhesive fluid is deposited in the recess and held therein by the adhesive film. Once the fluid is cured, the adhesive film is removed. The resulting slider assembly may then be patterned by etching. For example, the first and second air-bearing surfaces may be coated with an etch mask, which is then developed to allow for the patterning of the first and second air-bearing surfaces. U.S. Pat. No. 6,106,736 to LeVan et al. describes a similar method of preparing an air-bearing surface of a slider for etch patterning, except that a heated wax is employed in place of the curable acrylate adhesive.
In sum, the above-described approaches employ an encapsulant to fill the gaps between sliders to protect the edges of the sliders during patterning. However, these encapsulants suffer from a number of disadvantages. For example, the curable encapsulants described in Kurdi et al. and the waxes described in LeVan et al. often exhibit unfavorable bonding and/or debonding performance. In particular, cured epoxy materials, e.g., pure thermosetting epoxy resins, can be removed from sliders only with great difficulty and often leave significant material residue on the slider surfaces. In addition, the prior art encapsulants suffer from incompatibility with solvents that are used with the photolithographic techniques for patterning air-bearing surfaces. That is, the prior art encapsulants are mechanically unstable and are subject to solvation when exposed to fluids used in photolithographic techniques.
Recently, advances have been made with respect to slider assemblies comprising a plurality of sliders bonded by a solid debondable polymeric encapsulant. For example, silicon-containing polymeric encapsultants for forming slider assemblies are described in U.S. patent application Ser. No. 10/611,418, entitled “Sliders Bonded by a Debondable Silicon-Based Encapsulant,” inventors McKean et al., filed on Jun. 30, 2003. Similarly, styrene-based polymeric encapsulants such those containing acrylate or butadiene components are described in U.S. patent application Ser. No. 10/611,673, entitled “Sliders Bonded by a Debondable Encapsulant Containing Styrene and Butadiene Polymers,” inventors Miller et al., and U.S. patent application Ser. No. 10/611,317, entitled “Sliders Bonded by a Debondable Encapsulant Containing Styrene and Acrylate Polymers,” inventors McKean et al., each filed on Jun. 30, 2003.
Nevertheless, there exist opportunities in the art to provide alternatives to known encapsulants for forming slider assemblies. In particular, it has been discovered that an improved polymeric encapsulant may be prepared by polymerizing a mixture of monomers in a nonstoichiometric ratio